This application is directed to a shear assembly or shearing apparatus, and more particularly a shear useful for cutting hard, brittle materials, e.g., an amorphous metal having a Rockwell hardness on the order of 72. Amorphous metal is useful in transformers because of its exceptional magnetic properties that yield ultra-low core losses. For use in the transformer environment, a plural layer laminate structure of individual thin gauge metal is used. The amorphous metal has a glassy, non-crystalline structure that is hard, brittle, and stress sensitive. The combination of these various structural properties result in a material that has heretofore been difficult to cut. Particularly, either a burr was formed along the cut edge such as when cutting silicon steel, or the material would shatter when cutting an armophous material.
As is well known, a burr is formed along a cut edge as a result of the gap between the cutting edges of the blades. Typically, a shear assembly comprises a movable first blade that is reciprocated past a stationary second blade or bed knife. As the movable blade or knife moves downwardly across the bed knife, a shear force arises at contact between the blades and the workpiece. The resultant shear force may be broken down into components by simple vector addition, namely, a horizontal force component, i.e., the force of separation, and a vertically directed force component. To limit the size of the burr on the final cut workpiece, the separation force must be minimized so that a precise cut is achieved.
The subject invention is deemed to provide a new and improved shearing apparatus that counteracts the separation of the blades and dynamically urges the blades together during a cutting stroke.